1. Field of the Invention
The present invention relates to a printing apparatus including a roll sheet supporting apparatus and a sheet processing apparatus.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 08-175707 discusses a supporting apparatus of a roll sheet applicable to a printing apparatus. The roll sheet is formed by winding a sheet around an outer circumferential surface of a hollow core tube. A supporting apparatus which is fitted into both ends of the core tube of the roll sheet supports the roll sheet rotatably. The supporting apparatus includes a driven unit to which driving force is transmitted and a transmission member which transmits rotational force of the driven unit. In an inner circumferential surface of the hollow core tube, a flange fixing auxiliary member is provided near the both ends thereof to detachably support the supporting apparatus to the core tube. The transmission member is engaged with the flange fixing auxiliary member, so that the supporting apparatus is fixed to the roll sheet. The flange fixing auxiliary member is configured as a step portion projecting inside from the inner circumferential surface of the core tube. The step portion is integrally formed with the core tube or formed by inserting another member in the core tube.
With this configuration, replacement work of the roll sheet can be improved compared with the conventional method in which the roll sheet is fixed by penetrating a supporting shaft into the core portion of the roll sheet, since it is not necessary to insert a long shaft into the roll sheet.
When the supporting apparatus is fixed to the core tube in the printing apparatus, flexibility of the method for certainly fixing the supporting apparatus can be increased by providing the flange fixing auxiliary member. However, providing the flange fixing auxiliary member may increase configuration members or complexity of the core tube itself. Therefore, simpler configuration which does not use the flange fixing auxiliary member has been desired.
With or without the flange fixing auxiliary member, as a fixing method of the supporting apparatus, a configuration has been widely used in which a leading edge portion of the supporting apparatus presses the inner circumferential surface of the core tube or the flange fixing auxiliary member. However, in this configuration, when the supporting apparatus is attached to the core tube, an outer diameter of the leading edge portion of the supporting apparatus may enlarge wider than an inner diameter of the core tube or the flange fixing auxiliary member, so that the supporting apparatus may be prevented from being inserted into the core tube. As a result, the supporting apparatus cannot be attached properly to the end portion of the roll sheet. Further, when the supporting apparatus is inserted or when the leading edge portion of the supporting apparatus presses the inner circumferential surface of the core tube or the flange fixing auxiliary member, an impact is applied to the supporting apparatus, so that the supporting apparatus may be broken. Therefore, the configuration which can simply and certainly attach the supporting apparatus has been desired.